Apparatus for applying heat treatment to web material



P 1964 c. B. FETNER ETAL 3,150,354

APPARATUS FOR APPLYING HEAT TREATMENT TO WEB MATERIAL 3 Sheets-Sheet 1Filed Aug. 9, 1962 p 29, 1954 c. B. FETNER ETAL 3,150,864

APPARATUS FOR APPLYING HEAT TREATMENT TO WEB MATERIAL Filed Aug. 9, 19625 Sheets-Sheet 2 CAMPBELL B. FETNER. 45 and Cecu. WAYNE JARV \&

Zmuww A T TUBA 5K5 Se t. 29, 1964 c. B. FETNER ETAL 3,

APPARATUS FOR APPLYING HEAT TREATMENT TO WEB MATERIAL Filed Aug. 9, 19623 Sheets-Sheet 3 INVENTORS CAMPBELL B. Fe-m E2 and Cecu. WAYNE JAzvlsZMRM QMMW A TTORNE Y5 United States Patent 3 150 864 APPARATUS FUR APlLYlNG HEAT TREATMENT T0 WEB MATERIAL Campbell B. Fetner, Charlotte,N.C., and Cecil Wayne Jarvis, Rock Hill, S.C., assignors of fiftypercent to Gas Heat Engineering Corporation, Charlotte, N.C., acorporation of North Carolina, and fifty percent to Rock Hill Printingdz Finishing Company, Rock Hill, S.C.,

a corporation of Delaware Filed Aug. 9, 1962, Ser. No. 215,989 5 Claims.(Cl. 263-3) The present invention relates to improvements in anapparatus for applying a heat treatment to web material, such as atextile fabric. More particularly, the improved apparatus is of a typeuseful for drying textile fabrics, which have been dyed or printed, in amanner producing dyed or printed fabric of superior quality. Theapparatus is also capable of curing textile fabrics which have undergoneresin impregnation in a. fast and eflicient manner.

A problem common to the dyeing and printing of textile fabrics is thatof controlling color migration. Color migration is believed to be causedby the greater atlinity for moisture exhibited by the dyestuif appliedto the fabric as compared to the affinity of the dyestuff for the fabricitself. During a continuous drying operation in which dyed or printedfabric web material is being fed from a starting point in asubstantially continuous manner for undergoing a heat treatment whilethe fabric is moving, an attempt must be made to maintain an even dryingof the dyed or printed fabric to provide for even evaporation ofmoisture from the fabric which is necessary to control color migrationin the drying operation. Proposals for applying fairly uniform heatdistribution in a continuous drying operation across the surface areasof moving dyed or printed fabric webs have met with varying degrees ofsuccess. However, even the better proposals heretofore knowncharacteristically permit a relatively wide tolerance range in thedegree of heat maintained on the moving dyed or printed fabric weba 20F. tolerance range being typical. These proposals have included thedrying of web material by radiant heat emanating from an electric bulbor from a gas burner. produced radiant heat has been generally preferredfor a drying operation of this character because of the frequentoccurrence of discolored areas on the dyed or printed fabric caused bycombustion products produced from burning gas which have a tendency todull the coloration of the dyestuff.

However, the fairly uniform distribution of the heat applied to the dyedor printed textile fabrics has not produced a completely satisfactoryanswer to the problem of controlling color migration during a dryingoperation. In the latter respect, the application of heat treatments tomoving dyed or printed fabric webs by conventional procedures tends toconcentrate the heat on the opposite surfaces of the fabric web toevaporate moisture therefrom. This surface evaporation of moisture isresponsible for causing an irregular flow of moisture from the interiorregion of the fabric to the outer surfaces thereof, thereby unevenlydrawing a portion of the dyestulf which has penetrated into the fabricto the surfaces thereof. This phenomenon known as color migration, ifnot properly controlled, leads to color concentrations on the fabricwhich dull the coloration imparted to the fabric by the dyestuff andcause the dyed or printed fabric after it has been dried to take on anoutward appearance which may be described as lackluster or dingy.

The present invention therefore concerns an improved apparatus forapplying a heat treatment to Web material, such as a textile fabric,which is more effective in controlling color migration during the dryingof a moving dyed or printed fabric web. To this end, radiant infraredheat Electrically is relied upon as the drying agent. Infrared radiationoccurs over a wide range of wavelengths-extending from approximately 0.8micron to 1000 microns. It has been determined that certain wavelengthranges of infrared radiation are readily absorbed by water, whereasothers are not. By restricting the infrared radiation directed againstthe fabric to be dried to wavelength ranges lying within waterabsorption zones, we have found that the radiant heat penetrates throughthe fabric to be absorbed by the moisture therein for evenly evaporatingthe moisture on the opposite surfaces of the fabric and within theinterior region thereof to effectively control color migration. Ourinvention accomplishes thi purpose by providing an apparatus affording aprimary source of radiant infrared heat emanating from gas burnerslocated on opposite sides of the dyed or printed fabric web and havingheat transmissive and filtering shield means disposed between the gasburners and each of the opposite surfaces of the fabric web to be dried.The shield means protects the fabric web against exposure to theproducts of combustion from the gas burners, while transmitting radiantheat to the fabric web from the burners in a particular wavelength rangeof infrared radiation lying within a water absorption zone. In additionto acting as a heat transmissive means, the shield means also filtersout or absorbs some of the heat given off by the gas burners and in sodoing is heated itself to become a secondary source of radiant infraredheat of less intensity than the primary source and in a differentwavelength range lying within another water absorption zone of theinfrared radiation spectrum-this secondary source of infrared radiationbeing directed against the fabric web and combining with the greaterintensity of infrared radiation transmitted through the shield meansfrom the gas burners to m0dulate and distribute the infrared radiantheat over the fabric Web so as to penetrate throughout the thicknessthereof in a uniform manner to be absorbed by the moisture therein. Thistechnique of combining the infrared radiation from a primary source ofradiant heat with the infrared radiation developed in a heattransmissive and filtering shield means disposed between the primarysource of radiant heat and the fabric web to be dried has proved to benot only effective in reducing moisture flow from the interior region ofthe dyed or printed fabric web to its surfaces for controlling colormigration and stopping color concentration of the dyestuif impregnatedtherein during a drying operation, but it actually appears to beresponsible for developing or heightening the color of the dyestuffimpregnated in the fabric to provide a brightened,

lustrous coloration on the opposite surfaces of the fabric therebyproducing a finished dyed or printed fabric of superior quality comparedto dyed or printed fabrics which have been dried by conventionalapparatuses.

Accordinglly, it is a primary object of this invention to provide animproved apparatus for drying a dyed or printed fabric web whichsubstantially eliminates color concentration by controlling colormigration of the dyestuif to the opposite surfaces of the fabric webduring a drying operation in applying a heat treatment to the fabric webof infrared radiation in wavelength ranges lying within Water absorptionzones so that the radiant heat penetrates throughout the thickness ofthe fabric for evenly removing moisture therefrom.

It is another more specific object of this invention to provide animproved apparatus for drying a dyed or printed fabric web, wherein theapparatus comprises gas burners formin a primary source of radiantinfrared heat in combination with heat transmissive and filtering shieldmeans on each side of the fabric web with the shield means transmittingradiant heat to the fabric web from the burners in a predeterminedWavelength range of infrared radiation lying within a water absorptionzone, while absorbing some of the heat emanating from the burners tobecome a secondary source of radiant infrared heat directed to thefabric webthe secondary source of radiant infrared heat being in adifferent wavelength range and lying within another water absorptionzone of the infrared radiation spectrum to modulate the more intenseinfrared radiation transmitted to the fabric web through the shieldmeans from the burners comprising the primary source of radiant infraredheat. The complementary nature of the secondary source of radiantinfrared heat provided by the shield means when added to the primarysource of radiant infrared heat results in a greater development of thecolor of the dyestufl to produce a brightened, lustrous coloration onthe dyed or printed fabric web following the drying operation.

Some of the objects of the invention having been stated, other objectswill become apparent as the description proceeds, when taken inconnection with the accompanying dram'ngs in which FIGURE 1 is a sideelevational view of the improved apparatus for applying a heat treatmentto web material in accordance with the present invention, partiallybroken away and showing the assembly of the heating means in verticalsection for purposes of clarity;

FIGURE 2 is an enlarged vertical sectional view of one of the burnerelements illustrated in FIGURE 1;

FIGURE 3 is a fragmentary end elevational view of the improved apparatusfor applying a heat treatment to web material, looking at the left-handend of the apparatus as illustrated in FIGURE 1; and

FIGURE 3-A is a fragmentary view taken substantially along the line3-A-3-A in FIGURE 1, being partially in end elevation and partially invertical section, with parts shown in vertical section being broken awayfor purposes of clarityFIGURE 3-A forming a continuation of thefragmentary end elevational view of FIGURE 3 to illustrate a completeend of the apparatus.

Referring more specifically to the drawings, the apparatus in accordancewith the present invention comprises a housing including end walls andside walls, the housing 10 being supported on a floor or other planarsurface bypairs of legs 11, 11 located at the opposite sides thereof.The side walls of the housing 10 are provided with respective doors '12,12 therein, the doors 12, 12 being hingedly mounted about one sidethereof to the respective side wall corresponding thereto for pivotalmovement between open and closed positions to provide access to theinterior of the housing. The top and bottom of the housing 10 are opento permit Web material W, such as textile fabric, which is to besubjected to a heat treatment to be fed through the housing 10 in avertical path of travel intermediate the end walls thereof, as will bepresently described.

In the latter connection, it will be observed that upper and lower webfeed rolls 13, 14 are respectively mounted on the housing 10 so astoextend between the side walls thereof across'thetopen top and openbottom of the housing 10. Suitable pairs of bearing blocks 15, 16 areprovided on the housing 10 into which axles extending from opposite endsof the web feed rolls 13, 14 are journaled. The web material W is fedinto the housing 10 through the open bottom thereof by being directedonto the lower feed roll 14, and the web material W then passesupwardly' through the open top of the housing 10 on a vertical path oftravel, being received by the upper feed roll 13- from where the webmaterial W is directed away from the housing10.

Heating means are arranged within the interior of the housing 10 so asto extend along the opposite end walls thereof in opposed relationshipto the opposite surfaces of the web material W being fed through thehousing 10. In this respect, the heating means comprises upper ingelements 20 arranged along the interior surfaces of both end walls ofthe housing 10 so as to direct the major portion of heat generatedthereby inwardly of the housing 10 toward the web material W. Thus, anupper bank A of heating elements 20 and a lower bank B of heatingelements 2t) are located along the int rior surface of the left-hand endwall of the housing 10, as shown in FIGURE 1, while upper bank C andlower bank D are located along the interior surface of the right handend wall.

Since the arrangement of each of the upper and lower banks of heatingelements 2t along both end walls of the housing 10 is the same, it willbe understood that the following description of the upper bank A ofheating elements 2!; extending along the interior surface of theleft-hand end wall of the housing 10 as illustrated in FIGURE 1 willalso apply to the banks B, C, and D of heating elements 26. The upperbank A of heating elements 2i? along the interior surface of theleft-hand end wall includes first and second vertically spacedhorizontal rows of heating elements 20 extending widthwise of thehousing 10, each of the horizontal rows of heating elements 29comprising a plurality of adjoining elongate gas burners 21. Theopposite ends of the individual gas burners 21 are provided with lugs 22which abut corresponding lugs 22 of adjoining gas burners 21, and thegas burners 21 are connected together by suitable fastener boltsextending through the opposed abutting lugs 22, 22 on adjacent gasburners 21.

Each of the gas burners 21, as shown in FIGURE 2, comprises an elongatedhorizontally extending burner housing 23. The burner housing 23 istubular, being open at both ends, and includes top and bottomhorizontally extending walls 24, 25, a vertical back wall 26 disposedadjacent to the end wall of the apparatus housing it) correspondingthereto, and a vertical front wall 27 disposed inwardiy of the back wall26 with respect to the apparatus housing iii to provide a fuel chamber28 defined by the walls of the burner housing 23. It will be observedthat the top and bottom walls 24, 25 extend inwardly beyond the frontwall 27 of the burner housing 23 and terminate in vertical upstandingand depending flanges 29, 29 to which a burner screen assembly 3t) issecured. The burner screen assembly 30 comprises an inner verticallydisposed wire mesh screen Iii-i, an outer generally vertically disposedwire mesh screen 32 having a convex curvature and being spaced inwardlyof the apparatus housing in with respect to the inner screen 31, andsuitable bracket members for mounting the screens 31, 32 on the flanges29, 29 of the burner housing 23. The inner and outer screen 31, 32 aretherefore arranged in spaced overlying relation to the front wall 27 ofthe burner housing 23. The inner screen 31 cooperates with the frontwall 2'7, the inward extensions of the top and bottom walls 24, 25, andthe bracket members mounting it on the flanges 29, 29 of the burnerhousing 23 to define a combustion chamber 33. A burner orifice 34 isformed in the front wall 27 of the burner housing 23, being centrallypositioned therein with respect to the top and bot tom walls 24, 25 andintermediate the ends of the burner housing 23, for providingcommunication between the fuel chamber 28 and the combustion chamber 33.

A rod 35 extends through the fuel chamber 28 and the burner orifice 34,the rod 35 having a flame bafiie plate 36 on the end thereof projectingthrough the burner orifice 34 and being adjustably secured at its otherend to the back Wall 26 of the burner housing 23. Lengthwise adjustmentof the rod 35 with respect to the burner housing 23 regulates the degreeof restriction imposed on the burner orifice 34 by the flame baffleplate 36. The fiame baffle plate 36 will ordinarily be adjusted todiffuse the ignited gases issuing from the burner orifice 34 so that theflame of the gas burner 21 will spread across the area of the innerscreen 31 which serves as a burner grid. The inner screen or burner grid31 is thereby heated to become a heat radiating surface and the heatradiated therefrom combines with conducted heat and heat of convectionfrom the tlow of hot gases generated by the flame of the gas burner 21to uniformly heat the outer screen 32 so that it becomes a heatradiating surface furnishing a primary source of radiant infrared heatdirected inwardly of the apparatus housing 10. The inner screen orburner grid 31 and the outer screen 32 may be made of suitableheat-resistant mesh material, such as Nichrome mesh, the mesh of theinner screen or burner grid 31 being preferably more closely woven andof lighter Weight than the mesh of the outer screen 32.

It will be appreciated that the fuel chambers 23 of the plurality ofadjoining gas burners 21 in each of the several horizontal rows ofheating elements 26 included in tie banks A, B, C and D of heatingelements 29 define a continuous fuel passageway extending the length ofthe row, since the burner housings 23 of the gas burners 21 in the roware open at both ends. The horizontal rows of heating elements 20included in the upper and lower banks A, B of heating elements 20 alongone end wall of the apparatus housing are secured at one end thereof bymeans of respective brackets 37, 37 to a vertical support in the form ofan angle-iron member 443 (FIGURE 3-A) projecting laterally inward of theend wall corresponding to the banks A, B of heating elements 20. Theburner housings 23, 23 of the gas burners 21, 21 at one end of the firstand second horizontal rows of heating elements comprising each of thebanks A, B of heating elements 20 are attached to the respective bracket37 which serves as an end closure for the fuel passageways defined bythe adjoining fuel chambers 28 of the gas burners 2-1 comprising thefirst and second horizontal rows of heating elements 2i in each of thebanks A, B of heating elements Zii. It will be understood that thehorizontal rows of heating elements Zii included in the upper and lowerbanks C, D of heating elements 20 along the other end wall of theapparatus housing It are mounted Within the apparatus housing It at oneend thereof in a manner similar to that previously described inconnection with the upper and lower banks A, B of heating elements Zii.

As shown in FIGURE 1, a fuel manifold comprising a pair of branchmanifolds 41, all, is connected into a fuel supply piping system, aswill be later described. The branch manifolds 41, 41 extend verticallywithin the housing it) along the opposite end walls thereof and areconnected to the burner housings 23 of the gas burners 21 at the otherend of each of the first and second horizontal rows of heating elements29 included in the upper and lower banks A, B, C and D of heatingelements 259 by nozzles 42 (FIGURE 3) to provide communication be tweenthe branch manifolds 41, 41 and the fuel passageways defined by theadjoining fuel chambers 23 in each row of heating elements Ztl.

The fuel supply piping system includes an air line 43 extending belowthe housing lit and communicating with a source of compressed air (notshown). A gas supply conduit 44 is disposed above the air line 43(FIGURE 1) and is connected to a source of gas fuel (not shown) by a gastap line 45 (FIGURE 3). The flow of gas from the source of gas fuelthrough the gas tap line 45 to the gas supply conduit 44 is controlledby a manually operable valve 46 in the gas tap line 45, and the pressureof the gas flowing through the gas tap line 4-5 is regulated by apressure regulator 47 of the flexible diaphragm type which is alsointerposed in the gas tap line 45 adjacent to its connection with thegas supply conduit 44.

Compressed air from the an" line 43 is admitted to a mixing chamberprovided in a conical pipe fitting 59 through an air tap line 51 whichextends from the air line 43 and is connected to the conical pipefitting 53 by a pipe coupling 52. The air tap line 51 has a valve 53therein for controlling the flow of compressed air into the mixingchamber provided in the conical pipe fitting 50. The outlet end of thegas supply conduit 44 is also connected to the conical pipe fitting 563by the pipe coupling 52. The mixing chamber in the conical pipe fitting50 is in the form of a Venturi passageway. Thus, gas is drawn from thegas supply conduit 44 into the conical pipe fitting 5t and thereafterinto the branch manifolds il, 41 via a T -connector 54 joining thebranch manifolds 41, ll to the conical pipe fitting St) in response tothe vacuum created by the compressed air rushing through the pipecoupling 52 past the outlet end of the gas supply conduit 44 connectedthereinto to draw gas from the gas supply conduit 44 into the conicalpipe fitting 50.

The valve 53 in the air tap line 51 may be manually or automaticallyoperable to control the how of compressed air through the pipe coupling52 and past the outlet end of the gas supply conduit 44 for regulatingthe degree of the vacuum drawing gas from the gas supply conduit 44 intothe conical fitting 54). It will be understood that the valve 53 may beadjusted to Vary the degree of the vacuum. In the latter respect, thepressure regulator 47 is adjusted in accordance with the degree ofvacuum induced by the flow of compressed air in the manner described tocorrespondingly raise or lower the gas pressure flowing from the sourceof gas fuel through the gas tap line 45 to the gas supply conduit 44 forthereby increasing or decreasing the gas drawn into the conical pipefitting 50 from the gas supply conduit 44. Where the valve 53 is of anautomatically operable type, it is prefe erably controlled by amechanism relying upon a web temperature sensing means in the form of aradiation pyrometer trained on the surfaces of the web material W Withinthe interior of the housing 10 (not shown). The radiation pyrometersenses the temperature of the web material W within the housing 10 andis responsible for adjusting the valve 53 to increase or decrease theflow of compressed air from the air tap line 51 through the pipecoupling 52 and past the outlet end of the gas supply conduit 44 tocorrespondingly heighten or lessen the vacuum which increases ordecreases the pressure of the gas fuel passing into the gas supplyconduit 44 by appropriate adjustment of the pressure regulator 47. Inthis manner, the temperature of the web material W within the housingIt) can be maintained at a predetermined magnitude.

For further regulating the gas-air fuel mixture supplied to the burners21, the restriction of the Venturi passageway in the conical pipefitting 50 may be adjusted by a manually operable flow adjuster 55,which extends outwardly of and below the pipe coupling 52, to increaseor reduce the vacuum induced by the compressed air for increasing orreducing the amount of the gas-air fuel mixture drawn into the branchmanifolds 41, 41 from the gas supply conduit 44 and the air tap line 51.

A burner flame detector 55 is located in horizontal alinement with eachof the banks or groups A, B, C, D of heating elements 20, the burnerflame detectors 56 being positioned adjacent a side wall of theapparatus housing 10 (FIGURE 3A) and including inwardly projectingsensing tubes 57 which respectively terminate adjacent one of the endsof the banks or groups A, B, C, and D of heating elements 20. The burnerflame detectors 56 sense the presence of ultra-violet light in theflames produced by the gas burners 21. Should the flames of the gasburners 21 in a particular bank or group of heating elements 20 beextinguished while gas is being supplied to the banks or groups A, B, C,and D of heating elements 26, this condition will be detected by theburner flame detector 56 associated therewith because of the absence ofultra-violet light due to the lack of flames from the gas burners 21.The burner flame detector 56 associated with the non-firing bank orgroup of heating elements 20 will then communicate this condition to asuitable valve means (not shown) in the gas supply conduit 44 to closethe valve means for shutting oif the flow of gas from the gas supplyconduit 44 to the burners 21,

thereby averting a dangerous accumulation of gas in the apparatushousing 19.

Each of the upper and lower banks or groups A, B, C, and D of heatingelements 2t) are individually confined by generally inwardly convergentreflector casings--there being upper reflector casings 69, 6tcorresponding to the upper banks A, C of heating elements 2% and lowerreflector casings 61, 61 corresponding to the lower banks B, D ofheating elements 20. A plurality of exhaust holes 62 are provided in thelower reflector casings 61, 61 above the lower banks B, D of heatingelements 2 the exhaust holes 62 serving to dissipate products ofcombustion from the gas burners 21. The upper reflector casings 60, 6dsimilarly include exhaust holes (not shown) at appropriate locationstherein above the upper banks A, C of heating elements 2.0 to allowproducts of combustion from the gas burners 21 to escape through theupper reflector casings 60, 60' and upwardly through the open top of thehousing 14 Each of the upper and lower reflector casings 60, 6 and 61,61 converges inwardly to define a horizontally extending mouth disposedinwardly of the bank or group of heating elements 2t) associatedtherewith. The Upper and lower boundaries of each of the horizontallyextending mouths are outlined by trackways 63, 63 provided in therespective reflector casing. Means are positioned in the mouths of theupper and lower reflector casings 6t), 60 and 61, 61 to shield the webmaterial W from direct exposure to the gas flames and the products ofcombustion from the individual gas burners 21, and to transmit radiantheat to the web material W from the burners 21 in a particularwavelength range of infrared radiation lying within a water absorptionzone. Such means takes the form of a plurality of plate glass shields 64which are slidably mounted along their upper and lower edges inthe'trackways 63 of respective reflector casings so as to cover themouths thereof. While a plurality of glass shields 64 have been shownand described as covering each of the mouths, it will be understood thata continuous elongated glass plate extending across the entire length ofeach mouth may be suitably employed.

The plurality of glass shields 54 extend lyengthwise across each of thebanks or groups A, B, C, D of heating elements 26, being interposedbetween the heating ele ments and the web material W on each side of theweb material W as it is fedin a vertical path of travel through theapparatus housing 1th. Thus, the glass shields 64 protect the webmaterial W against direct exposure to the gas flames and the products ofcombustion from the gas burners 21, while transmitting radiant heat tothe web material W from the burners 21 as described. Additionally, theglass shields 64 also filter out or absorb some of the heat given off bythe gas burners 21 and become heated to an extent, wherein the glassshields 6 provide a secondary source of radiant infrared heat of lessintensity than the' primary source of radiant infrared heat emanatingfrom the gas burners 21. This secondary source of radiant infrared heatfrom the glass shields 64 is transmitted to the web material W in adifferent wavelength range lying within another water absorption zone ofthe infrared radiation spectrum. It has been found that this secondarysource of infrared radiation fromthe heated glass shields 64 combineswith the greater intensity of infrared radiation transmitted through theglass shields 64 from the primary source of infrared radiation afforded'by the gas burners 21 tomodulate and distribute the infrared radiantheat over the web material W so that the radiated heat from theapparatus uniformly penetrates throughout the thickness of the webmaterial W to be absorbed by the moisture therein.

In this manner, the apparatus accomplishes the drying of dyed or printedfabric web material in a superior fashion as compared to dryingapparatuses heretofore used for this purpose by effectively controllingcolor migration of the dyestuff impregnated in the dyed or printedfabric web material. This improved drying of dyed or printed fabric webmaterial by the apparatus is accompanied by a greater development orheightening of the color of the dyestuif impregnated in the fabric webmaterial which provides a brightened, lustrous coloration on theopposite surfaces of the fabric web material as compared to dyed orprinted fabric web materials which have been dried by conventionalprocedures. It is believed that this brightened, lustrous coloration ofthe fabric web material after it has been dried by the apparatus inaccordance with this invention is brought about by the evenly modulatedand distributed infrared radiant heat applied to the fabric web materialwhich is afforded by transmitting infrared radiation toward the fabricweb material from primary and secondary sources of infrared radiation indifferent wavelength ranges and lying within water absorption zones ofthe infrared radiation spectrum.

By means of the present apparatus, printed or dyed fabric web materialmay be subjected to the maximum, practical amount of radiant heat lyingWithin a water absorption range of the infrared radiation spectrum whichcan be safely employed without singeing or burning of the web material.In this respect, We have determined that the primary source of infraredradiation transmitted through the glass shields 64 from the gas burners21 should have a wavelength of the order of 2.436 microns, this beingthe most effective wavelength of infrared radiation to be transmittedfrom the primary heat source to obtain fast and efficient evaporation ofmoisture from the web material W. 2.436 microns of infrared radiationlies within a water absorption zone of the infrared radiation spectrumand is that predominantly produced at a temperature of approximately1,680 P. from the gas burners 21, or a radiation of approximately 36,090B.t.u.s/ft. /hr.

The glass shields 64 may be made of a suitable heatresistant materialcapable of transmitting radiant heat and filtering out or absorbing heatto become a heat radiating element, such as Feurex glass or Pyrex glass.By way of example, Feurex glass shields 64- having a thickness of /21inch by virtue of absorbing and filtering out certain heat from the gasburners 21 associated therewith may be heated to become a secondarysource of infrared radiation transmitting radiant heat to the webmaterial W having a wavelength ranging between 5 and 6 microns or withinanother water absorption range of the infrared radiation spectr'um5.lmicrons being the approximate wavelength of infrared radiation obtainedfrom the Feurex glass shields 64 and directed toward the web material W.5.1 microns of infrared radiation is that predominantly produced at atemperature of approximately 563 F. or a radiation of approximately1,889

B.t.u.s'/ft.2/hr. The Feurex glass shields 64 transmit approximately 83percent of the radiant heat energy at 2.436 microns from the gas burners21 associated therewith, the balance of the heat being absorbed orfiltered out by the glass shields 64 in becoming a secondary source ofradiant infrared heat.

Since the gas burners 21 in the upper and lower banks A, B, C, and D ofheating elements 20 can be carefully regulated as to the amount ofradiant infrared heat derived therefrom to be transmitted through theglass shields 64 toward the web material W by varying the amount of thegas-air fuel mixture admitted thereto through the fuel supply pipingsystem in accordance with pyrometer readings of the temperature of theweb material W within the apparatus, a much closer temperature tolerancerange can be maintained with respect to the temperature of the webmaterial than the 20 F. tolerance range typically accompanying the useof conventional drying apparatuses. In this connection, the heatingmeans within the apparatus in accordance with the present invention canbe controlled to produce a predetermined temperature on the web materialbeing dried which is held within a tolerance range of only 5-7 F.therebyattesting to 9 the uniformity of the radiant heat applied to dyed orprinted fabric web material by the instant apparatus.

From the standpoint of operating economies and strict control on theamount of heat radiated from the primary source of infrared radiation,gas burners are considered to be preferable as the primary source ofinfrared radiation in the improved apparatus. It should be understood,however, that it is within the spirit of the present invention to employelectrical heating means as the primary source of infrared radiation inconjunction with the glass shields 64 as the secondary source ofinfrared radiation.

The apparatus is also suitable in curing web material, such as a textilefabric, which has been treated with resins. In this respect, the resinimpregnated in a fabric web material can be quickly cured by bringingthe temperature of the web material up to the desired curing temperaturethrough proper regulation of the radiant infrared heat emanating fromthe gas burners 21 with curing of the resin being accomplished in a fastand efiicient manner.

While we have illustrated and described a single apparatus for applyinga heat treatment to web material, it is contemplated that a plurality ofthese apparatuses may be suitably arranged in end-to-end relationshipwith a common fuel supply piping system for processing web materialthrough a drying or curing operation as will appear more fully in ourco-pending US. application, Serial No. 215,990, filed August 9, 1962.

In the drawings and specification there has been set forth a preferredembodiment of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not for thepurposes of limitation, the scope of the invention being defined in theclaims.

We claim:

1. In an apparatus for applying a heat treatment to web material havinga moisture content,

(a) a heating means for radiating toward said web material infrared heatpredominantly of wave lengths lying within a first water absorption Zoneat approximately 2.436 microns of the infrared radiation spectrum,

(b) heat transmissive and absorptive shield means adapted to beinterposed between said heating means and said web material (b) fordirectly transmitting from said heating means to said web material amajor portion of said infrared heat of wave lengths lying within saidfirst water absorption zone and (b") for absorbing other of saidinfrared heat and itself radiating to said web material infrared heatpredominantly of wave lengths lying within a second water absorptionzone at approximately 5.1 microns of the infrared radiation spectrum.

2. In an apparatus for applying a heat treatment to web material havinga moisture content,

(a) heating means for radiating toward the opposite surfaces of said webmaterial infrared heat predominantly of Wave lengths lying within afirst water absorption zone at approximately 2.436 microns of theinfrared radiation spectrum,

(b) heat transmissive and absorptive shield means adapted to beinterposed between said heating means and said web material (1)) fordirectly transmitting from said heating means to the opposite surfacesof said web material a major portion of said infrared heat of wavelengths lying within said first water absorption zone and (b") forabsorbing other of said infrared heat and thereby becoming heated, andfor thereafter itself radiating to the opposite surfaces of said webmaterial infrared heat predominantly of wave lengths lying within asecond water ab- 1t) sorption' zone at approximately 5.1 microns of theinfrared radiation spectrum.

3. In an apparatus for applying a heat treatment to a web of textilematerial and the like,

(a) means for feeding said web along a predetermined path of travel,

(b) heating means mounted adjacent said predetermined path of travel forradiating toward the opposite surfaces of said web fed therealonginfrared heat predominantly of wave lengths lying within a first waterabsorption zone at approximately 2.436 microns of the infrared radiationspectrum,

(c) heat transmissive and absorptive shield means adapted to beinterposed between said heating means and said predetermined path oftravel (0') for directly transmitting from said heating means to theopposite surfaces of said Web fed along said predetermined path a majorportion of said infrared heat of wave lengths lying wiithin said firstwater absorption zone and (0) for absorbing other of said infrared heatand thereby becoming heated, and for thereafter itself radiating to theopposite surfaces of said web fed along said predetermined path infraredteat predominantly of wave lengths lying within a second waterabsorption zone at approximately 5.1 microns of the infrared radiationspectrum.

4. In an apparatus for applying a heat treatment to a web of textilematerial and the like having a moisture content,

(a) a housing having an open top,

(b) means for feeding said web through said housing along apredetermined path of travel,

(c) gas heating means mounted within said housing and adjacent oppositesides of said predetermined path of travel for radiating toward theopposite surfaces of said web fed through said housing infrared heatpredominantly of Wave lengths lying within a first water absorption zoneat approximately 2.436 microns of the infrared radiation spectrum,

(d) substantially planar heat transmissive and absorptive shield meansmounted within said housing and adapted to be interposed between saidheating means and said predetermined path of travel (d) for directlytransmitting from said heating means to the opposite surfaces of saidweb fed through said housing a major portion of said infrared heat ofwave lengths lying within said first Water absorption zone and (d") forabsorbing other of said infrared heat and thereby becoming heated, andfor thereafter itself radiating to the opposite surfaces of said web fedthrough said housing infrared heat predominantly of wave lengths lyingwithin a second water absorption zone at approximately 5.1 microns ofthe infrared radiation spectrum.

5. In an apparatus for applying a heat treatment to a web of textilematerial and the like having a moisture content,

(a) a housing having an open top and bottom, and

a pair of substantially parallel vertical walls,

(b) means disposed across the top and bottom of said housing for feedingsaid web along a substantially Vertical straight path of travel throughsaid housing between said vertical walls of said housing,

(c) heating means mounted adjacent said path of travel for radiatingtoward the opposite surfaces of said web fed through said housinginfrared heat predominantly of wave lengths lying Within a first waterabsorption zone at approximately 2.436 microns of the infrared radiationspectrum,

(d) said heating means comprising a plurality of gas burners mountedwithin said housing in substantially 11 horizontally extending straightrows along said pair of verticalwalls' of said housing, at least one. ofsaid straight rows of said gas burners extending along each of saidp'airof vertical walls, and said gas burners being directly inwardly ofsaid housing toward said path of travel for radiating said infrared heatin opposing directions toward the opposite surfaces of said web fedthrough said housing,

(e) heat transmissive and absorptive shield rneans adapted to beinterposed between said gas burners and said path of travel ('e") fordirectly transmitting from said gas' burners to the opposite surfaces ofsaid web fed through said housing a major portion of said infrared heatof wave lengths lying within said first water absorption zone and (e")for absorbing other of said infrared heat and thereby becoming heated,and for thereafter itself radiating to the opposite surfaces of web fedthrough said housing infrared heat predominantly of wave lengths lyingWithin a second water absorption zone at approximately 5.1 microns ofthe infrared radiation spectrum,

(f) said shield means comprising a plurality of substantially planarglass plates respectively associated with said gas burners along each ofsaid pair of vertical walls of said housing and positioned inwardly ofsaid gas sburners corresponding thereto between said gas burners and theopposite surfaces of said web fed through said housing, said glassplates eX- tending substantially horizontally in parallel relationshipto the respective opposite surfaces of said web fed through said housingand covering all of said gas burners in said rows to protect theopposite surfaces of said web material from direct exposure to theflames and products of combustion from said gas burners.

References Cited in the file of this patent UNITED STATES PATENTS2,980,410 Edvar Apr. 18, 1961 3,020,032 Casey Feb. 6, 1962 FOREIGNPATENTS 535,753 Belgium Feb. 28, 1955 1,129,123 France July 13, 1955

1. IN AN APPARATUS FOR APPLYING A HEAT TREATMENT TO WEB MATERIAL HAVINGA MOISTURE CONTENT, (A) A HEATING MEANS FOR RADIATING TOWARD SAID WEBMATERIAL INFRARED HEAT PREDOMINANTLY OF WAVE LENGTHS LYING WITHIN AFIRST WATER ABSORPTION ZONE AT APPROXIMATELY 2.436 MICRONS OF THEINFRARED RADIATION SPECTRUM, (B) HEAT TRANSMISSIVE AND ABSORPTIVE SHIELDMEANS ADAPTED TO BE INTERPOSED BETWEEN SAID HEATING MEANS AND SAID WEBMATERIAL (B'') FOR DIRECTLY TRANSMITTING FROM SAID HEATING MEANS TO SAIDWEB MATERIAL A MAJOR PORTION OF SAID INFRARED HEAT OF WAVE LENGTHS LYINGWITHIN SAID FIRST WATER ABSORPTION ZONE AND (B") FOR ABSORBING OTHER OFSAID INFRARED HEAT AND ITSELF RADIATING TO SAID WEB MATERIAL INFRAREDHEAT PREDOMINANTLY OF WAVE LENGTHS LYING WITHIN A SECOND WATERABSORPTION ZONE AT APPROXIMATELY 5.1 MICRONS OF THE INFRARED RADIATIONSPECTRUM.